Dyeing Process on a Woven Product for the Purpose of Faded Effects Comprising an Application of Mordant Before Weaving, the Dyeing Being Deferred Until After Weaving

ABSTRACT

The invention relates to a dyeing or mordant process preferably for the purpose of obtaining faded effects on woven products or garments, characterized in that the mordant is applied to the warp yarn (or conversely the weft yarn) before the weaving, while the weft yarn (or conversely the warp yarn) constitutes the resist, and in that the dyeing is deferred until after the weaving. 
     Advantageously, the mordant and a sizing product are applied simultaneously to the warp yarn. 
     The dyeing can be carried out before or after making up.

The present invention relates to a novel process for the dyeing of woven products.

The object of the invention is to obtain faded effects on woven products, effects inspired by the spirit of the woven products referred to as “faded blue jeans”, by a simple process and within a broad palette of shades and effects, while significantly reducing in particular manufacturing circuits, the costs of logistics and the industrial costs.

It should be remembered here that a woven product with a “faded blue jeans” appearance is obtained by weaving a warp yarn, dyed indigo beforehand according to a dyeing technique specific to this colourant, over an undyed weft yarn constituting a resist and by then fading the said woven product.

As indigo produces only a single hue which is specific to it, the appearance has been seen, in order to produce other shades or hues, of novel materials comprising a dyed warp yarn, the latter being either dyed by a colourant which is supposed to be fadeable (certain “sulphur” colourants, for example, which give black and brown hues) or coloured according to a pigment system also capable of being fadeable.

However, in all cases, the warp yarn receives its colour before the weaving.

In order to carry out these dyeing processes before weaving, it is necessary to employ complex and expensive techniques which are available solely in large companies. As the cost of the industrial process is not within the reach of small and medium-sized companies, it constitutes a major disadvantage in carrying out the processes of the prior art. In addition, the costs of storage, logistics and transportation are very high as the choice of the shades and of the amounts has to be managed upstream of the weaving and of the making up. The long waiting period brought about makes it necessary to take risks before the trend in fashion is known and results in losses and/or unsold stock.

There also exist woven products with an “unfaded effect” obtained by dyeing and weaving weft yarns and warp yarns of different materials which react differently to dyeing (example: polyester and cotton). The invention makes it possible, for its part, to produce similar effects on products, the weft and warp of which are made of the same material (for example, 100% cotton).

The present invention is targeted at overcoming the abovementioned disadvantages by a novel process for dyeing woven products of the type comprising an application of a mordant, characterized in that the mordant is applied to the warp yarn (or conversely the weft yarn) before the weaving, while the weft yarn (or conversely the warp yarn) constitutes the resist, and in that the dyeing is deferred until after the weaving.

Advantageously, the mordant and a sizing product are applied simultaneously to the warp yarn.

The dyeing carried out after the weaving can be carried out before or after the making up of the garment.

The invention also relates to the woven products, which may or may not be made up and which may or may not be faded, obtained with the process and in particular to the products which are 100% in the same material (for example, 100% cotton).

Furthermore, the prior art cites the documents U.S. Pat. No. 2,205,887, GB 2 233 352 and U.S. Pat. No. 3,960,477, which describe “resist” dyeing techniques, that is to say techniques according to which the treated yarn does not dye, while the untreated yarn does dye. In other words, these three techniques operate “negatively” by application of a resist to one part, followed by development of the colour on the other part.

Conversely, in the process according to the invention, the treated yarn is dyed, while the untreated yarn resists dyeing, this treatment of the treated yarn (warp or weft) being carried out by the application of a mordant before weaving. In other words, the process according to the invention operates “positively” by application of a mordant to one part and then by development of the colour on the same part.

A better understanding of the invention will be obtained with the help of the description which follows:

Unlike the existing processes, the warp yarn is not coloured before the weaving but receives a mordant which will allow it to be coloured after the weaving, the weft yarn constituting a resist, as in the prior processes.

This principle can also be extended by reversing the treatments on the warp yarns and the weft yarns.

The dyeing stage is carried out after weaving, either before the making up of the garment or after it has been made up.

A process according to the invention thus comprises the following successive stages:

-   -   stage of mordanting the yarns,     -   stage of weaving,         then:     -   either stage of dyeing before stage of making up a garment,     -   or stage of making up a garment before stage of dyeing.

If a fading is required, it can be carried out before or after making up, simultaneously or not with the dyeing.

In all the scenarios, the storage and/or transportation operations can take place either after the weaving or after the dyeing or after the making up and the capability of being able to dye after weaving or after making up constitutes a new advantage resulting in significant savings in preparation, storage, transportation and time.

Two categories are distinguished in the preparation of the yarns:

-   -   a first yarn, which receives a mordant; this application can be         carried out on any scoured, bleached, indeed even ecru, yarn by         the usual continuous or batchwise processes. In the case of the         warp yarn conventionally sized before weaving, it will be found         to be advantageous to include the mordant in the sizing. The         size-mordant mixture here forms the product christened compound         and prepared from compatible components observing the desired         functions of sizing and of mordanting.     -   a second yarn, constituting a resist.

The weaving is carried out conventionally and according to any known type of weave.

The mordanted yarns (first yarn) are dyed by any conventional means on woven products, before or after making up the garment.

The choice of the colourants is made according to their affinity for the mordant, their yield and their fastness, while taking into account the level of resist required on the resist yarns (second yarn).

The fading treatments take place after the dyeing, according to conventional equipment and processes, and preferably after making up, in order to obtain the effect referred to as “stitching effect” which marks the stitches of the garment.

A fixing agent can also be applied before or after fading, in a way known per se, in order to improve the fastness of the dyeings and/or of the effects.

The advantages of the invention are in particular as follows:

-   -   large reduction in the cost as the operation is carried out         (mordanting, weaving, making up, delivering) on undyed         materials, resulting in         -   saving with regard to aqueous and heat treatments and saving             with regard to products,         -   saving in logistics, transportation and handling,         -   reduction in the manufacturing circuit and in the material             stored,     -   delivery time reduced from several weeks to a few days,     -   choice of the dyeing shades made after making up, rather than         before weaving, thus at the time where the fashion-forming trend         becomes apparent, which reduces the number of items of woven         products or of garments of colour to be managed and makes it         possible to respond to demand,     -   large choice of shades and effects, because the choice and the         amount thereof are deferred until making up, whereas the         conventional technique requires the production of large minimum         yardages,     -   process which can be adapted to any weaving weave without         restriction,     -   the materials thus prepared to receive the process remain fully         adaptable to the usual applications, the mordant being removed         by simple washing,     -   possibility of using fibres other than cotton and yarns with a         technical effect, such as, for example, flame effect yarns,     -   possibility of being able to incorporate a visible or invisible         marker in the warp yarn or in the weft yarn in order to         authenticate the manufacture.

The definitions of the terms used are restated here:

MORDANT:

Any product applied to the material which subsequently makes it possible to receive a colouring material.

Example: a cationic mordant receiving an anionic colourant.

COLOURANT:

Any dyeing or pigmentary colouring material having the capability of being received by a mordant.

SIZES:

Any product which makes possible the sizing of the warp yarns.

COMPOUND:

Mixture of sizes and of mordants introducing the desired result.

The choice of the various sizes to be mixed with the various mordants is made according to the dyeing and fading effects which they produce.

RESIST AGENT:

Product which makes it possible for the material impregnated with it to resist dyeing. 

1. Process for dyeing woven products of the type comprising an application of a mordant, characterized in that the mordant is applied to the warp yarn (or conversely the weft yarn) before the weaving, while the weft yarn (or conversely the warp yarn) constitutes the resist, and in that the dyeing is deferred until after the weaving.
 2. Process according to claim 1, characterized in that the mordant and a sizing product are applied simultaneously to the warp yarn.
 3. Process according to either of claims 1 and 2, characterized in that a marker is applied before the weaving.
 4. Process according to one of claims 1 to 3, characterized in that the dyeing is carried out after the weaving and before the making up of the garment.
 5. Process according to one of claims 1 to 3, characterized in that the dyeing is carried out after the making up of the garment.
 6. Process according to one of claims 1 to 5, characterized in that a fading is additionally carried out after or at the same time as the dyeing.
 7. Process according to one of claims 1 to 6, characterized in that the application of the mordant can be carried out on any type of scoured, bleached, ecru yarn.
 8. Uncoloured woven product which may or may not be made up into a garment, characterized in that it is obtained by a process according to one of claims 1 to
 3. 9. Woven product which may or may not be made up into a garment, characterized in that it is dyed by a process according to one of claims 4 to
 7. 10. Woven product according to either of claims 8 and 9, characterized in that it is produced with weft yarns and warp yarns which are identical in the nature of the fibres.
 11. Woven product according to claim 8 or claim 10, characterized in that the yarn receiving the mordant is a scoured or bleached or ecru yarn. 